James Cameron is preparing a chronicle of his expedition to the bottom of the Mariana Trench as a TV special for National Geographic and a 3D release in cinemas.

His seven-mile (11km) descent in Deepsea Challenger to the ocean's lowest point in the western Pacific was the deepest solo dive ever.

Cameron said in a phone interview on Tuesday that the film could be ready late this year or early next year.

He completed his expedition on Monday, then rushed to London for the premiere of a 3D version of his 1997 blockbuster Titanic, which is released next week in time for the 100th anniversary of the ship's sinking.